Method of optimizing transmission, and transmitter

ABSTRACT

The invention relates to a method of optimizing transmission, and a transmitter receiving digital signals, in which the transmitter is used in a radio system to optimally transmit the signals. The transmitter includes modulation means arranged to modulate the received signals, and converter means for converting the digital signal into an analog signal before signal transmission. The position of the signal received by the converter means within the dynamic range of the converter means affects optimality of the signal obtained from the conversion. The transmitter further include means for generating weighting coefficients, and means for weighting each modulated signal by a specific weighting coefficient so as to set the mutual power levels of the signals into predetermined relations and to optimally dispose the signals within the dynamic range of the converter means. In addition, the transmitter includes means for combining the weighted signals, after which the converter means converts the combined signal into an analog signal, and means for scaling the signal converted into the analog signal into a predetermined power level.

FIELD OF THE INVENTION

The invention relates to a method of optimizing transmission, whichmethod is used at a transmitter receiving several digital signals thatare modulated, which transmitter comprises converter means converting asignal into an analog signal before signal transmission, and in whichmethod the position of the signal to be converted within the dynamicrange of the converter means affects optimality of the signal obtainedfrom the conversion.

The invention also relates to a transmitter receiving digital signals,which transmitter is used in a radio system to optimally transmitsignals, the transmitter comprising modulation means arranged tomodulate the received signals, and converter means converting thedigital signal into an analog signal before signal transmission, theposition of the signal received by the converter means within thedynamic range of the converter means affecting optimality of the signalobtained from the conversion.

DESCRIPTION OF THE PRIOR ART

In prior art radio systems, such as GSM radio systems, a signal comingfrom the direction of a fixed network usually propagates to a basestation via a mobile exchange and a base station controller. The basestation operating as a transmitter receives a digital signal coming fromthe direction of a fixed PSTN network and forwards the signal to asubscriber terminal. Depending on the radio system used, the basestation also has information on directing the signal to be transmittedinto the desired timeslot, for example. In addition, the base stationhas information on the power level at which the signal is transmitted,for example. Generally, the base station transmits signals to subscriberterminals at different power levels according to instructions obtainablefrom the radio system. When transmitting the signal, the base stationoperates as a transmitter.

The base station performs various types of codings, such as channelcoding, to data comprising the received signal, after which digitalsignals coming from different channels are modulated. After themodulation, the signals are converted into analog signals, after whichthe signals are combined in the analog parts of the transmitter. Next,the combined signal is amplified and transmitted onto a radio path.

The spectrum of a signal transmitted by a prior art transmitter, such asa base station, comprises various types of interference caused by theconversion of digital signals into analog signals and by the combiningof the signals. The base station receives signals whose frequencies andpower levels are usually very different. Problems are particularlycaused by signals coming to a DIA converter at different power levels,since, in prior art solutions, constant optimal utilization of thedynamic range of the converter is impossible. In addition, convertersavailable at the moment cannot tolerate interference in the signal wellenough. After the combination, the signals with different power levelsalso bring about interference, particularly to adjacent channels.

EP 735 702 discloses a signal reception method employing the weightingof the received signal. However, the method disclosed in the prior artdiffers from the one disclosed in the application, for example, in thatin the method disclosed in the prior art, signals are not set into acorrect mutual relation after they are combined and converted intoanalog signals. In addition, the method disclosed in the prior art isused in signal reception, whereas the one disclosed in the applicationis used at a transmitter.

EP 263 357 discloses a reception method in which signals are receivedwith several antennas. The received signals are combined by usingweighting coefficients. The method disclosed in the prior art is used insignal reception, whereas the one disclosed in the application is usedat a transmitter. Furthermore, in the method disclosed in the prior art,the manner of weighting the signal differs from the one in the methoddisclosed in the application.

EP 807 988 discloses a method of generating weighting coefficients. Thedisclosed method differs from the one disclosed in the application inthat in the method disclosed in the prior art, no reference is made tocombining the weighted signal and converting the combined signal into ananalog signal, for example.

The method disclosed in EP 806 844 differs from the one disclosed in theapplication in that it is used at a receiver. The method disclosed inthe prior art uses weighting coefficients, but the weightingcoefficients are feed-back-controlled.

JP 921 9615 discloses a transceiver structure using a reference signalfor calculating weighting coefficients. In addition, adaptive antennaarrays are used at the transceiver. It is not necessary to use antennaarrays in the solution of the application. In addition, a referencesignal as disclosed in the prior art is not used in the method disclosedin the application.

BRIEF DESCRIPTION OF THE INVENTION

An object of the invention is to provide a method and transmitter tosolve the above problems. This is achieved by a method of the typepresented in the introduction, which is characterized in that eachmodulated signal is weighted by a specific weighting coefficient so asto set the mutual power levels of the signals into predeterminedrelations and to optimally dispose the signals within the dynamic rangeof the converter means, the signals are combined after the weighting,and the combined signal is converted into an analog signal, after whichthe combined signal is scaled to a predetermined power level.

The transmitter is characterized in that it comprises means forgenerating weighting coefficients, means for weighting each modulatedsignal by a specific weighting coefficient so as to set the mutual powerlevels of the signals into predetermined relations and to optimallydispose the signals within the dynamic range of the converter means,means for combining the weighted signals, after which the means convertthe combined signal into an analog signal, and means for scaling thesignal converted into the analog signal to a predetermined power level.

The preferred embodiments of the invention are disclosed in thedependent claims.

The invention is based on the idea that a signal coming to a DIAconverter is so processed that after the processing, the signal utilizesthe dynamic range of the converter as optimally as possible. In thesolution of the invention, the dynamics the D/A converter is optimizedwhen several digitally modulated signals are combined. This is done intwo phases. In a first phase, the power levels of the signals are setinto a correct relation with one another in such a way that the dynamicsof the converter becomes optimally utilized. The modulated signals arecombined, after which the combined signal is set to the absolutelycorrect power level.

The method and transmitter of the invention provide many advantages. Themethod enables conversion of digital signals at different power levelsinto analog signals in such a way that a signal coming to thetransmitter even at a very low power level is converted by optimallyutilizing the dynamic range of a converter. This is implemented in sucha way that each received signal is weighted by a weighting coefficientmatched to the signal, whereby the word length of the signal can bematched to the maximum word length of the converter, and problems causedby different signal power levels are thus solved. The transmitter can beimplemented with fewer analog parts or by combining analog parts,whereby the transmitter can be implemented at a lower cost. In addition,the transmitter tolerates interference much better than previouslyimplemented transmitters. Furthermore, the transmitter of the inventionconsumes less power than prior art transmitters, since the number ofanalog parts consuming power can be reduced, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in more detail bymeans of preferred embodiments with reference to the accompanyingdrawings, in which:

FIG. 1 shows a radio system comprising a number of transmitters that usethe method of the invention,

FIG. 2. shows the transmitter of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a radio system comprising a number of base stations 100 anda base station controller 200. Furthermore, the radio system comprises anumber of subscriber terminals 300. The base stations 100 are connectedto the base station controller 200 via a fixed transmission network, forexample. The base stations 100 receive a digital signal coming from thePSTN (Public Switched Telephone Network) and being converted into ananalog signal that is forwarded via a radio path to the subscriberterminals 300. In other words, the base stations 100 operate astransceivers.

FIG. 2 shows a transmitter that can be used in the radio systempresented in FIG. 1. In practice, the transmitter is located in the basestation 100. For its part, the transmitter generates a signal to betransmitted to the subscriber terminal 300. The transmitter comprises anumber of means 110, and means 130. In addition, the transmittercomprises means 190 receiving a signal from the means 110, 130. Themeans 110 receive a digital signal coming from the PSTN, for example,and modulate the received signal preferably by a digital modulationmethod. The transmitter according to the figure uses the DDS method(Direct Digital Synthesis) by means of which the modulated signal isbrought to the desired frequency.

The means 110 modulate several different signals, and each signalestablishes different connections to the subscriber terminals 300. Theconnections can be calls, for example. Each modulated signal has itsspecific power level, indicated by S_level in the figure. The means 130generate, on the basis of the power levels of the signals received bythe transmitter, weighting coefficients (PC_(i)) that are applied to themeans 190. The transmitter according to the figure receives foursignals, and for each of them, the means 130 generate a weightingcoefficient indicated by PC₁ . . . PC₄. In practice, the power level ofthe signal is proportional to the amplitude of the signal, for example.

The transmitter also comprises means 140 that is connected to the means190 and combines signals coming from the means 190. The transmitterfurther comprises means 170, 180, and converter means 120. The convertermeans 120 receive the signal that is combined by the means 140 andconvert it into an analog signal. Next, the analog signal is applied tothe means 180 that change the power level of the received signal.Besides weighting coefficients, the means 130 also generate, on thebasis of the power levels of the signals received by the means 110,scaling factors (CTRL_VGA) that are converted into an analog signal inthe means 170. In practice, the means 170 are implemented by a D/Aconverter. The analog signal generated by the means 170 is applied tothe means 180. The means 180 change, on the basis of the signal comingfrom the means 170, the power level of the signal coming from theconverter means 120. In other words, the signal coming from the means170 is used as a control signal. In practice, the means 180 areimplemented by a VGA amplifier (Variable Gain Amplifier), for example,whose amplification changes in connection with the change of the controlsignal.

In practice, the converter means 120 are implemented by a D/A converter.An optimal word length having, for example, the same length as themaximum word length accepted by the converter means 120 can be selectedfor the signal coming to the converter means 120 via the means 140. Insome cases, the conversion of a signal in the converter means 120 can beoptimally carried out when the converter means 120 receive a signalsubstantially equivalent to the width of the dynamic range of theconverter means, for example.

The means 130 generate weighting coefficients by using signals receivedby the transmitter. The means 190 weight each modulated signal by aweighting coefficient proportional to the received signals. The means190, which are operationally connected to the means 110, 130, generate,from the modulated signal and from the weighting coefficientproportional to the modulated signal, a result that substantiallycorresponds to multiplication. The weighting distributes the modulatedsignal optimally over the dynamic range of the converter means 120. Inother words, as regards the converter 120, the signals are disposedwithin the optimal range. The means 130 can optimally weight the signalcoming to the converter means 120 in such a way that the word length ofthe digital signal increases towards the maximum word length accepted bythe converter means 120, for example.

The means 190 weight each modulated signal by a specific weightingcoefficient so as to set the mutual power levels of the signals intopredetermined relations. In this case, a predetermined relation refersto a relation or a ratio between the signals, the ratio being obtainedfrom the relations of the mutual power levels predetermined for thesignal. In the weighting, each signal is further optimally disposedwithin the dynamic range of the converter means 120. In the weighting,the means 190 set the power levels of the signals into predeterminedrelations according to the specific power level in each signal duringthe modulation. The power levels of the signals coming from the means110 to the means 190 are the same. The means 110 modulate the signals tothe same power level in such a way that the power levels of the signalsare at the same level before they are weighed. In the weighting, themeans 190 change the mutual relation of the signal power levels comparedwith the relations of the power levels of the received signals.

Let us assume that the width of the dynamic range of the converter means120 is 13 bits. Let us also assume that a signal having a word length of14 bits is obtained from the output of the means 110. In this case, ifthe signal obtained from the output of the means 110 is weighted by aweighting coefficient proportional to the power level (S_level) of thesignal, a signal word length of 10 bits may then be obtained at theinput of the converter means 120. In the above mentioned situation, themeans 130 change the weighting coefficient (PC_(i)) associated with thesignal to 0.5, whereby the word length of the signal coming from themeans 110 may be changed to 13 bits. In the above-described situation,it is also assumed that the full scale of the converter means 120corresponds to the optimal range. Next, the signal obtained from theoutput of the converter means 120 is again weighted by a signal(CTRL_VGA) that is obtained from the means 130 and generates a scalingfactor. In the above described situation, the means 130 generate ascaling factor whose value is 0.125.

The means 130 generate a weighting coefficient in such a way that themeans 130 measure the power level of the signal received by thetransmitter, for example. The means can also obtain information on themagnitude of the power level in some other manner. When the means 130obtain information on the magnitude of the power level of the signal,the means 130 multiply or, similarly thereto, weight the maximum wordlength accepted by the converter means 120 by the measured power levelvalue. On the basis of the above mentioned calculation, the obtainedmultiplication result is divided, similarly to the multiplication, bythe sum of the power levels of the modulated signals. Instead ofdividing, the multiplication result can also be weighed by the inverseof the sum of the modulated signal power levels. In other words, thetransmitter of the invention enables more efficient utilization of thecapacity of the converter means 120. The means 130 generate weightingcoefficients for each signal received by the transmitter bysubstantially using the following formula (1), or an equivalent formula:$\begin{matrix}{{{PC}_{i} = {{S\_ Level}_{i}*( \frac{{{Max\_}{DAC}}{\_ {Scale}}}{\sum\limits_{j}\quad {S\_ {Level}}_{j}} )}},} & (1)\end{matrix}$

where

PC_(i) stands for the weighting coefficient,

S_Level_(i) stands for the power level of the received signal,

Max_DAC_Scale is a constant defining the maximum of the conversionversion range of the converter means,$\sum\limits_{j}\quad {S\_ Level}_{j}$

stands for the sum of the power levels of the signals.

The means 130 also generate scaling factors by using the signalsreceived by the transmitter. The scaling factors are applied to themeans 180 via the means 170. Next, the means 180 scale, by using thescaling factors, the signal converted into the analog signal to apredetermined power level or amplitude, defining signal intensity. Themeans 180 scale the signals that form the combined signal to the desiredpower level by the same scaling factor. In practice, the means 180 areimplemented by an amplifier. The amplifier amplifies or attenuates, onthe basis of the scaling factor generated by the means 130, the analogsignal coming from the means 120. The means 180 dynamically adjust theabsolute power level of the signal to the desired level.

The means 130 sum the power levels of the signals received by thetransmitter, after which the means 130 divide the summing result by themaximum word length value accepted by the converter means 120. Insteadof dividing, the summing result can be weighted, i.e. multiplied by theinverse of the maximum word length value accepted by the converter means120. The means 130 substantially generate the scaling factors by thefollowing formula (2), or an equivalent formula:. $\begin{matrix}{{{{CTRL}\_ {VGA}} = ( \frac{\sum\limits_{j}{{S\_}{Level}}_{j}}{{Max\_ DAC}{\_ Scale}} )},} & (2)\end{matrix}$

where

PC_(i) stands for the weighting coefficient,

S_Level_(i) stands for the power level of the received signal,

Max_DAC_Scale is a constant defining the maximum of the conversion rangeof the converter means, $\sum\limits_{j}\quad {S\_ Level}_{j}$

stands for the sum of the power levels of the signals,

CTRL_VGA stands for the scaling factor.

In the following, the solution of the invention is described concerningone modulated signal. Let a signal obtained from the means 110 be IN₁,for example. Also, let a signal obtained from the output of the means120 be INT₁, for example. The means 130 generate a weighting coefficientPC₁ that is proportional to the power level of the received signal andalso to the IN₁ signal. In that case, after the operation executed bythe means 190, the INT₁ signal is 30 obtained from the output of themeans 190, and receives the value IN₁*PC₁. Let us also assume that themeans 130 generate a scaling factor CTRL_VGA by means of which theweighted signal is restored to the desired power level. Let a signalobtained from the output of the means 180 be OUT₁. The OUT₁ signal canbe presented in the following way:

 OUT ₁ =INT ₁ *CTRL _(—) VGA=IN ₁ *PC ₁ *CTRL _(—) VGA=IN ₁ *S_level₁.

In addition, the transmitter preferably comprises means 150, 160,disposed between the means 140 and 120. The means 150 round the value ofthe combined signal obtained from the means 140 to a proximate value.The means 160 add a random signal to the combined signal. Adding therandom signal reduces interference in the signal before the signal isconverted into an analog signal. Adding the random signal particularlyreduces the effects of harmonic waves and quantization noise on thesignal.

In the following, the method of the invention is described concerningthe weighting coefficients (PC_(i)) that are used in the method and setthe modulated signals into a mutually correct weighting relation. Let usassume that the power level, or the signal level, S_level_(—)1 of afirst signal is four. Let us also assume that the power levelS_level_(—)2 of a second signal is three. PC₂ then obtains the value ¾*PC₁, in which case the signals obtained from the output of the means 110are correctly pre-weighted with regard to one another. Let us assumethat after the modulation, the power levels of the signals obtained fromthe output of the means 110 are at level one. If the optimum numberrange of the converter means 120 is 14, PC₁ may then be eight, wherebyPC₂ is six (PC₁+PC₂=14). The values weighted by the weightingcoefficient PC_(i) bear now a correct relation with regard to oneanother. After the combining, the modulated signals also bear a correctpower level in relation to one another. However, the signals are not yetabsolutely correctly weighted.

Let us assume that a symbol MOD₁ refers to a signal that is obtainedfrom the output of the means 110 and weighted by the coefficient PC₁.Let us also assume that a symbol MOD₂ refers to a signal that isobtained from the output of the means 110 and weighted by thecoefficient PC₂. Consequently, a signal having the valuePC₁*MOD₁+PC₂*MOD₂ is received from the output of the means 140. Next,the means 130 generate a scaling factor whose value is ½. The signalobtained from the output of the means 140 is multiplied by the scalingfactor, whereby a signal whose value is 4*MOD₁+3*MOD₂ is obtained as aresult. The value of the signal is thus in accordance with the originalS_level values, in other words, the signals are also absolutelycorrectly weighted.

Although the invention is described above with reference to the exampleaccording to the accompanying drawings, it is obvious that the inventionis not restricted to it but it can be modified in a variety of wayswithin the scope of the inventive idea disclosed in the attached claims.

What is claimed is:
 1. A method of optimizing transmission, which methodis used at a transmitter receiving several digital signals that aremodulated, which transmitter includes converter means converting asignal into an analog signal before signal transmission, and in whichmethod the position of the signal to be converted within the dynamicrange of the converter means affects optimality of the signal receivedby the conversion, the method comprising: weighting each modulatedsignal by a specific weighting coefficient so as to set the mutual powerlevels of the signals into predetermined relations and to optimallydispose the signals within the dynamic range of the converter means,combining the signals after weighting, converting the combined signalinto an analog signal, and scaling the combined signal to apredetermined power level.
 2. The method of claim 1, wherein, in theweighting, the power levels of the signals are set into predeterminedrelations according to a specific power level in each signal during themodulation.
 3. The method of claim 1, wherein, in the weighting, themutual relation of the power levels of the signals is changed.
 4. Themethod of claim 1, wherein the signals are modulated to the same powerlevel.
 5. The method of claim 1, wherein the signals that form thecombined signal are scaled to the desired power level by the samescaling factor.
 6. The method of claim 5, wherein the scaling factor isgenerated by summing the power levels of the received signals, afterwhich the summing result is divided or weighted by a maximum word lengthvalue accepted by the converter means.
 7. The method of claim 1,wherein, in the scaling, a scaling factor converted into an analogsignal is used.
 8. The method of claim 1, wherein the scaling restoresthe power level of each signal that forms the combined signal to thepower level in the signal before the signal modulation.
 9. The method ofclaim 1, wherein, in the weighting, the word length of the signal ismatched to the optimum word length of the converter means.
 10. Themethod of claim 1, further comprising rounding the word length of thecombined signal to a word length proximate thereto or to a pre-desiredword length.
 11. The method of claim 1, further comprising adding arandom signal to the combined signal to reduce interference therein. 12.The method of claim 1, wherein the weighting coefficient is generated bymeasuring the power level of the received signal, after which themaximum signal word length value accepted by the converter means ismultiplied or, similarly thereto, weighted by the measured power levelvalue, and the received multiplication result is divided or weighted bythe sum of the power levels of the modulated signals.
 13. The method ofclaim 1, wherein the signals are modulated by a digital modulationmethod in which each signal is set to a specific frequency by a DirectDigital Synthesis method.
 14. The method of claim 1, wherein eachmodulated signal is weighed by the specific weighting coefficientsubstantially obtained by the following formula:${{PCi} = {{S\_ {Level}}_{i}*( \frac{{Max\_ DAC}{\_ Scale}}{\sum\limits_{j}\quad {{S\_}{Level}}} )}},$

where PCi stands for the weighting coefficient, S_Level_(j) stands forthe power level of the received signal, Max_DAC Scale is a constantdefining the maximum of the conversion range of the converter means,$\sum\limits_{j}\quad {S\_ Level}_{j}$

 stands for the sum of the power levels of the signals.
 15. The methodof claim 1, wherein the analog signal is scaled by the scaling factorsubstantially obtained by the following formula:${{{CTRL}\_ {VGA}} = ( \frac{\sum\limits_{j}\quad {S\_ {Level}}_{j}}{{Max\_ DAC}{\_ Scale}} )},$

where CTRL_VGA stands for the scaling factor, Max_DAC_Scale a constantdefining the maximum of the conversion range of the converter means, and$\sum\limits_{j}\quad {S\_ Level}_{j}$

 stands for the sum of the power levels of the signals.
 16. Atransmitter receiving digital signals, which transmitter is used in aradio system to optimally transmit signals, the transmitter comprisingmodulation means arranged to modulate the received signals, andconverter means for converting the digital signal into an analog signalbefore signal transmission, the position of the signal received by theconverter means affecting optimality of the signal obtained from theconversion, the transmitter comprising: means for generating weightingcoefficients, means for weighting each modulated signal by a specificweighting coefficient so as to set the mutual power levels of thesignals into predetermined relations so as to optimally position thesignals within the dynamic range of the converter means, means forcombining the weighted signals, after which the converter means convertthe combined signal into an analog signal, and means for scaling thesignal converted into the analog signal to a predetermined power level.17. The transmitter of claim 16, wherein the means for weighting set thepower levels of the signals into predetermined relations according tothe specific power level in the signal during the modulation.
 18. Thetransmitter of claim 16, wherein the means for weighting change themutual relation of the power levels of the signals.
 19. The transmitterof claim 16, wherein the modulation means modulate the signals to thesame power level in such a way that the power levels of the signals areat the same level before the weighting of the signals.
 20. Thetransmitter of claim 16, wherein the scaling means scale the signalsthat form the combined signal to the desired power level by the samescaling factor.
 21. The transmitter of claim 16, wherein the scalingmeans scale the signals that form the combined signal by the samescaling factor.
 22. The transmitter of claim 16, wherein the scalingmeans set the signals that form the combined signal to the desired powerlevel.
 23. The transmitter of claim 16, wherein the weighting meansmatch the signal coming to the converter means to the optimum wordlength of the converter means.
 24. The transmitter of claim 16, whereinthe weighting means form, from the modulated signal and from theweighting coefficient proportional to said modulated signal, a resultthat substantially corresponds to the multiplication.
 25. Thetransmitter of claim 16, further comprising means for rounding the wordlength of the combined signal to a word length proximate thereto or to apre-desired word length.
 26. The transmitter of claim 16, furthercomprising means for adding a random signal to the combined signal toreduce interference in the combined signal before the conversion of thesignal into an analog signal.
 27. The transmitter of claim 16, whereinthe means for generating weighting coefficients measure the power levelof the signal received by the transmitter, after which the meansmultiply or, similarly thereto, weight the maximum word length valueaccepted by the converter means by the measured power level value, andthe obtained multiplication result is divided or weighted by the sum ofthe power levels of the modulated signals to generate the weightingcoefficient.
 28. The transmitter of claim 16, wherein the means forgenerating the scaling factors generate scaling factors used in thescaling, the weighting means weight by the generated scaling factor, andthe analog signal generated by the converter means to a predeterminedpower level.
 29. The transmitter of claim 16, wherein the means forgenerating the weighting coefficient generate the scaling factor bysumming the power levels of the signals received by the transmitter anddividing or weighting the summing result by the maximum signal wordlength value accepted by the converter means.
 30. The transmitter ofclaim 16, furthering comprising scaling factor conversion means that areoperationally connected to the means for generating weightingcoefficients and that convert the scaling factor used in the scalinginto an analog signal.
 31. The transmitter of claim 16, wherein thescaling means are implemented by an amplifier amplifying or attenuating,on the basis of the scaling factor generated by the means for generatingweighting coefficients, the analog signal coming from the convertermeans.
 32. The transmitter of claim 16, wherein the modulation meansmodulate the signal by a digital modulation method.
 33. The transmitterof claim 16, wherein during modulation, the modulating means sets eachsignal to its specific operating frequency by a Direct Digital Synthesismethod.
 34. The transmitter of claim 16, wherein the means forgenerating weighting coefficients generates the weighting coefficientsfor each signal received by the transmitter by substantially using thefollowing formula:${{PCi} = {{S\_ {Level}}_{j}*( \frac{{Max\_ DAC}{\_ Scale}}{\sum\limits_{j}\quad {{S\_}{Level}}} )}},$

where PCi stands for the weighting coefficient, S_Level_(j) stands forthe power level of the received signal, Max_DAC Scale is a constantdefining the maximum of the conversion range of the converter means, and$\sum\limits_{j}\quad {S\_ Level}_{j}$

 stands for the sum of the power levels of the signals.
 35. Thetransmitter of claim 16, wherein the means for generating weightingcoefficients generates the scaling factors used in the scaling bysubstantially using the following formula:${{{CTRL}\_ {VGA}} = ( \frac{\sum\limits_{j}{{S\_}{Level}}_{j}}{{Max\_ DAC}{\_ Scale}} )},$

where CTRL_VGA stands for the scaling factor, Max_DAC_Scale a constantdefining the maximum of the conversion range of the converter means, and$\sum\limits_{j}\quad {S\_ Level}_{j}$

 stands for the sum of the power levels of the signals.